The radii of two spheres are in the ratio `1 : 2`. Find the ratio of their surface areas.

Answer

`1 : 4`

Explanation

Let the radii of the two spheres be x and 2x respectively.
Then, `(S_(1))/(S_(2)) = (4pi x^(2))/(4pi (2x)^(2)) = (x^(2))/(4x^(2)) = (1)/(4) rArr S_(1) : S_(2) = 1 : 4`